buffer: Unify `git_fbuffer` and `git_buf`

This makes so much sense that I can't believe it hasn't been done
before. Kill the old `git_fbuffer` and read files straight into
`git_buf` objects.

Also: In order to fully support 4GB files in 32-bit systems, the
`git_buf` implementation has been changed from using `ssize_t` for
storage and storing negative values on allocation failure, to using
`size_t` and changing the buffer pointer to a magical pointer on
allocation failure.

Hopefully this won't break anything.

16 files changed, 158 insertions, 157 deletions

diff --git a/src/attr_file.c b/src/attr_file.c
index 7911381ea..a1b69a5bb 100644
--- a/src/attr_file.c
+++ b/src/attr_file.c
@@ -111,7 +111,7 @@ int git_attr_file__from_file(
 	git_repository *repo, const char *path, git_attr_file *file)
 {
 	int error = GIT_SUCCESS;
-	git_fbuffer fbuf = GIT_FBUFFER_INIT;
+	git_buf fbuf = GIT_BUF_INIT;
 
 	assert(path && file);
 
@@ -120,9 +120,9 @@ int git_attr_file__from_file(
 
 	if (error == GIT_SUCCESS &&
 		(error = git_futils_readbuffer(&fbuf, path)) == GIT_SUCCESS)
-		error = git_attr_file__from_buffer(repo, fbuf.data, file);
+		error = git_attr_file__from_buffer(repo, fbuf.ptr, file);
 
-	git_futils_freebuffer(&fbuf);
+	git_buf_free(&fbuf);
 	if (error != GIT_SUCCESS)
 		git__rethrow(error, "Could not open attribute file '%s'", path);
 
diff --git a/src/buffer.c b/src/buffer.c
index 183da7c5f..b9f62cc30 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -7,14 +7,17 @@
 #include "buffer.h"
 #include "posix.h"
 #include <stdarg.h>
+#include <ctype.h>
 
 /* Used as default value for git_buf->ptr so that people can always
  * assume ptr is non-NULL and zero terminated even for new git_bufs.
  */
 char git_buf_initbuf[1];
 
+static char git_buf__oom;
+
 #define ENSURE_SIZE(b, d) \
-	if ((ssize_t)(d) > buf->asize && git_buf_grow(b, (d)) < GIT_SUCCESS)\
+	if ((d) > buf->asize && git_buf_grow(b, (d)) < GIT_SUCCESS)\
 		return GIT_ENOMEM;
 
 
@@ -31,8 +34,10 @@ void git_buf_init(git_buf *buf, size_t initial_size)
 int git_buf_grow(git_buf *buf, size_t target_size)
 {
 	int error = git_buf_try_grow(buf, target_size);
-	if (error != GIT_SUCCESS)
-		buf->asize = -1;
+	if (error != GIT_SUCCESS) {
+		buf->ptr = &git_buf__oom;
+	}
+
 	return error;
 }
 
@@ -41,17 +46,17 @@ int git_buf_try_grow(git_buf *buf, size_t target_size)
 	char *new_ptr;
 	size_t new_size;
 
-	if (buf->asize < 0)
+	if (buf->ptr == &git_buf__oom)
 		return GIT_ENOMEM;
 
-	if (target_size <= (size_t)buf->asize)
+	if (target_size <= buf->asize)
 		return GIT_SUCCESS;
 
 	if (buf->asize == 0) {
 		new_size = target_size;
 		new_ptr = NULL;
 	} else {
-		new_size = (size_t)buf->asize;
+		new_size = buf->asize;
 		new_ptr = buf->ptr;
 	}
 
@@ -64,7 +69,6 @@ int git_buf_try_grow(git_buf *buf, size_t target_size)
 	new_size = (new_size + 7) & ~7;
 
 	new_ptr = git__realloc(new_ptr, new_size);
-	/* if realloc fails, return without modifying the git_buf */
 	if (!new_ptr)
 		return GIT_ENOMEM;
 
@@ -83,7 +87,7 @@ void git_buf_free(git_buf *buf)
 {
 	if (!buf) return;
 
-	if (buf->ptr != git_buf_initbuf)
+	if (buf->ptr != git_buf_initbuf && buf->ptr != &git_buf__oom)
 		git__free(buf->ptr);
 
 	git_buf_init(buf, 0);
@@ -98,12 +102,12 @@ void git_buf_clear(git_buf *buf)
 
 int git_buf_oom(const git_buf *buf)
 {
-	return (buf->asize < 0);
+	return (buf->ptr == &git_buf__oom);
 }
 
 int git_buf_lasterror(const git_buf *buf)
 {
-	return (buf->asize < 0) ? GIT_ENOMEM : GIT_SUCCESS;
+	return (buf->ptr == &git_buf__oom) ? GIT_ENOMEM : GIT_SUCCESS;
 }
 
 int git_buf_set(git_buf *buf, const char *data, size_t len)
@@ -162,11 +166,12 @@ int git_buf_printf(git_buf *buf, const char *format, ...)
 		va_end(arglist);
 
 		if (len < 0) {
-			buf->asize = -1;
+			free(buf->ptr);
+			buf->ptr = &git_buf__oom;
 			return GIT_ENOMEM;
 		}
 
-		if (len + 1 <= buf->asize - buf->size) {
+		if ((size_t)len + 1 <= buf->asize - buf->size) {
 			buf->size += len;
 			break;
 		}
@@ -205,9 +210,9 @@ void git_buf_consume(git_buf *buf, const char *end)
 	}
 }
 
-void git_buf_truncate(git_buf *buf, ssize_t len)
+void git_buf_truncate(git_buf *buf, size_t len)
 {
-	if (len >= 0 && len < buf->size) {
+	if (len < buf->size) {
 		buf->size = len;
 		buf->ptr[buf->size] = '\0';
 	}
@@ -238,7 +243,7 @@ char *git_buf_detach(git_buf *buf)
 	return data;
 }
 
-void git_buf_attach(git_buf *buf, char *ptr, ssize_t asize)
+void git_buf_attach(git_buf *buf, char *ptr, size_t asize)
 {
 	git_buf_free(buf);
 
@@ -372,3 +377,13 @@ int git_buf_join(
 
 	return error;
 }
+
+void git_buf_rtrim(git_buf *buf)
+{
+	while (buf->size > 0) {
+		if (!isspace(buf->ptr[buf->size - 1]))
+			break;
+
+		buf->size--;
+	}
+}
diff --git a/src/buffer.h b/src/buffer.h
index 3969f461e..3e9cb1713 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -11,7 +11,7 @@
 
 typedef struct {
 	char *ptr;
-	ssize_t asize, size;
+	size_t asize, size;
 } git_buf;
 
 extern char git_buf_initbuf[];
@@ -47,7 +47,7 @@ int git_buf_try_grow(git_buf *buf, size_t target_size);
 void git_buf_free(git_buf *buf);
 void git_buf_swap(git_buf *buf_a, git_buf *buf_b);
 char *git_buf_detach(git_buf *buf);
-void git_buf_attach(git_buf *buf, char *ptr, ssize_t asize);
+void git_buf_attach(git_buf *buf, char *ptr, size_t asize);
 
 /**
  * Test if there have been any reallocation failures with this git_buf.
@@ -83,7 +83,7 @@ int git_buf_puts(git_buf *buf, const char *string);
 int git_buf_printf(git_buf *buf, const char *format, ...) GIT_FORMAT_PRINTF(2, 3);
 void git_buf_clear(git_buf *buf);
 void git_buf_consume(git_buf *buf, const char *end);
-void git_buf_truncate(git_buf *buf, ssize_t len);
+void git_buf_truncate(git_buf *buf, size_t len);
 void git_buf_rtruncate_at_char(git_buf *path, char separator);
 
 int git_buf_join_n(git_buf *buf, char separator, int nbuf, ...);
@@ -115,4 +115,7 @@ GIT_INLINE(int) git_buf_rfind_next(git_buf *buf, char ch)
 	return idx;
 }
 
+/* Remove whitespace from the end of the buffer */
+void git_buf_rtrim(git_buf *buf);
+
 #endif
diff --git a/src/config_file.c b/src/config_file.c
index c9c7d11eb..ce76493c7 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -73,7 +73,7 @@ typedef struct {
 	git_hashtable *values;
 
 	struct {
-		git_fbuffer buffer;
+		git_buf buffer;
 		char *read_ptr;
 		int line_number;
 		int eof;
@@ -151,6 +151,7 @@ static int config_open(git_config_file *cfg)
 	if (b->values == NULL)
 		return GIT_ENOMEM;
 
+	git_buf_init(&b->reader.buffer, 0);
 	error = git_futils_readbuffer(&b->reader.buffer, b->file_path);
 
 	/* It's fine if the file doesn't exist */
@@ -164,14 +165,14 @@ static int config_open(git_config_file *cfg)
 	if (error < GIT_SUCCESS)
 		goto cleanup;
 
-	git_futils_freebuffer(&b->reader.buffer);
+	git_buf_free(&b->reader.buffer);
 
 	return GIT_SUCCESS;
 
  cleanup:
 	free_vars(b->values);
 	b->values = NULL;
-	git_futils_freebuffer(&b->reader.buffer);
+	git_buf_free(&b->reader.buffer);
 
 	return git__rethrow(error, "Failed to open config");
 }
@@ -765,7 +766,7 @@ static int skip_bom(diskfile_backend *cfg)
 {
 	static const char utf8_bom[] = "\xef\xbb\xbf";
 
-	if (cfg->reader.buffer.len < sizeof(utf8_bom))
+	if (cfg->reader.buffer.size < sizeof(utf8_bom))
 		return GIT_SUCCESS;
 
 	if (memcmp(cfg->reader.read_ptr, utf8_bom, sizeof(utf8_bom)) == 0)
@@ -847,7 +848,7 @@ static int config_parse(diskfile_backend *cfg_file)
 	git_buf buf = GIT_BUF_INIT;
 
 	/* Initialize the reading position */
-	cfg_file->reader.read_ptr = cfg_file->reader.buffer.data;
+	cfg_file->reader.read_ptr = cfg_file->reader.buffer.ptr;
 	cfg_file->reader.eof = 0;
 
 	/* If the file is empty, there's nothing for us to do */
@@ -976,10 +977,9 @@ static int config_write(diskfile_backend *cfg, const char *key, const regex_t *p
 		cfg->reader.read_ptr = NULL;
 		cfg->reader.eof = 1;
 		data_start = NULL;
-		cfg->reader.buffer.len = 0;
-		cfg->reader.buffer.data = NULL;
+		git_buf_clear(&cfg->reader.buffer);
 	} else {
-		cfg->reader.read_ptr = cfg->reader.buffer.data;
+		cfg->reader.read_ptr = cfg->reader.buffer.ptr;
 		cfg->reader.eof = 0;
 		data_start = cfg->reader.read_ptr;
 	}
@@ -1093,7 +1093,7 @@ static int config_write(diskfile_backend *cfg, const char *key, const regex_t *p
 
 			/* And then the write out rest of the file */
 			error = git_filebuf_write(&file, post_start,
-						cfg->reader.buffer.len - (post_start - data_start));
+						cfg->reader.buffer.size - (post_start - data_start));
 
 			if (error < GIT_SUCCESS) {
 				git__rethrow(error, "Failed to write the rest of the file");
@@ -1128,7 +1128,7 @@ static int config_write(diskfile_backend *cfg, const char *key, const regex_t *p
 		goto cleanup;
 	}
 
-	error = git_filebuf_write(&file, cfg->reader.buffer.data, cfg->reader.buffer.len);
+	error = git_filebuf_write(&file, cfg->reader.buffer.ptr, cfg->reader.buffer.size);
 	if (error < GIT_SUCCESS) {
 		git__rethrow(error, "Failed to write original config content");
 		goto cleanup;
@@ -1155,7 +1155,7 @@ static int config_write(diskfile_backend *cfg, const char *key, const regex_t *p
 	else
 		error = git_filebuf_commit(&file, GIT_CONFIG_FILE_MODE);
 
-	git_futils_freebuffer(&cfg->reader.buffer);
+	git_buf_free(&cfg->reader.buffer);
 	return error;
 }
 
diff --git a/src/fileops.c b/src/fileops.c
index 3241c68b1..d2b4af51e 100644
--- a/src/fileops.c
+++ b/src/fileops.c
@@ -97,87 +97,77 @@ mode_t git_futils_canonical_mode(mode_t raw_mode)
 		return 0;
 }
 
-int git_futils_readbuffer_updated(git_fbuffer *obj, const char *path, time_t *mtime, int *updated)
+int git_futils_readbuffer_updated(git_buf *buf, const char *path, time_t *mtime, int *updated)
 {
 	git_file fd;
 	size_t len;
 	struct stat st;
-	unsigned char *buff;
 
-	assert(obj && path && *path);
+	assert(buf && path && *path);
 
 	if (updated != NULL)
 		*updated = 0;
 
-	if (p_stat(path, &st) < 0)
-		return git__throw(GIT_ENOTFOUND, "Failed to stat file %s", path);
+	if ((fd = p_open(path, O_RDONLY)) < 0) {
+		return git__throw(GIT_ENOTFOUND, "Failed to read file '%s': %s", path, strerror(errno));
+	}
 
-	if (S_ISDIR(st.st_mode))
-		return git__throw(GIT_ERROR, "Can't read a dir into a buffer");
+	if (p_fstat(fd, &st) < 0 || S_ISDIR(st.st_mode) || !git__is_sizet(st.st_size+1)) {
+		close(fd);
+		return git__throw(GIT_EOSERR, "Failed to stat file '%s'", path);
+	}
 
 	/*
 	 * If we were given a time, we only want to read the file if it
 	 * has been modified.
 	 */
-	if (mtime != NULL && *mtime >= st.st_mtime)
-		return GIT_SUCCESS;
+	if (mtime != NULL && *mtime >= st.st_mtime) {
+		close(fd);
+		return 0;
+	}
 
 	if (mtime != NULL)
 		*mtime = st.st_mtime;
-	if (!git__is_sizet(st.st_size+1))
-		return git__throw(GIT_ERROR, "Failed to read file `%s`. An error occured while calculating its size", path);
 
 	len = (size_t) st.st_size;
 
-	if ((fd = p_open(path, O_RDONLY)) < 0)
-		return git__throw(GIT_EOSERR, "Failed to open %s for reading", path);
+	git_buf_clear(buf);
 
-	if ((buff = git__malloc(len + 1)) == NULL) {
-		p_close(fd);
+	if (git_buf_grow(buf, len + 1) < 0) {
+		close(fd);
 		return GIT_ENOMEM;
 	}
 
-	if (p_read(fd, buff, len) < 0) {
-		p_close(fd);
-		git__free(buff);
-		return git__throw(GIT_ERROR, "Failed to read file `%s`", path);
+	buf->ptr[len] = '\0';
+
+	while (len > 0) {
+		ssize_t read_size = p_read(fd, buf->ptr, len);
+
+		if (read_size < 0) {
+			close(fd);
+			return git__throw(GIT_EOSERR, "Failed to read from FD");
+		}
+
+		len -= read_size;
+		buf->size += read_size;
 	}
-	buff[len] = '\0';
 
 	p_close(fd);
 
 	if (mtime != NULL)
 		*mtime = st.st_mtime;
+
 	if (updated != NULL)
 		*updated = 1;
 
-	obj->data = buff;
-	obj->len = len;
-
-	return GIT_SUCCESS;
-}
-
-int git_futils_readbuffer(git_fbuffer *obj, const char *path)
-{
-	return git_futils_readbuffer_updated(obj, path, NULL, NULL);
+	return 0;
 }
 
-void git_futils_fbuffer_rtrim(git_fbuffer *obj)
+int git_futils_readbuffer(git_buf *buf, const char *path)
 {
-	unsigned char *buff = obj->data;
-	while (obj->len > 0 && isspace(buff[obj->len - 1]))
-		obj->len--;
-	buff[obj->len] = '\0';
+	return git_futils_readbuffer_updated(buf, path, NULL, NULL);
 }
 
-void git_futils_freebuffer(git_fbuffer *obj)
-{
-	assert(obj);
-	git__free(obj->data);
-	obj->data = NULL;
-}
-
-
 int git_futils_mv_withpath(const char *from, const char *to, const mode_t dirmode)
 {
 	if (git_futils_mkpath2file(to, dirmode) < GIT_SUCCESS)
diff --git a/src/fileops.h b/src/fileops.h
index 4c114026b..43ef21521 100644
--- a/src/fileops.h
+++ b/src/fileops.h
@@ -17,17 +17,8 @@
  *
  * Read whole files into an in-memory buffer for processing
  */
-#define GIT_FBUFFER_INIT {NULL, 0}
-
-typedef struct { /* file io buffer */
-	void *data; /* data bytes	*/
-	size_t len; /* data length */
-} git_fbuffer;
-
-extern int git_futils_readbuffer(git_fbuffer *obj, const char *path);
-extern int git_futils_readbuffer_updated(git_fbuffer *obj, const char *path, time_t *mtime, int *updated);
-extern void git_futils_freebuffer(git_fbuffer *obj);
-extern void git_futils_fbuffer_rtrim(git_fbuffer *obj);
+extern int git_futils_readbuffer(git_buf *obj, const char *path);
+extern int git_futils_readbuffer_updated(git_buf *obj, const char *path, time_t *mtime, int *updated);
 
 /**
  * File utils
diff --git a/src/ignore.c b/src/ignore.c
index 30f86b822..a3bf0a282 100644
--- a/src/ignore.c
+++ b/src/ignore.c
@@ -11,7 +11,7 @@ static int load_ignore_file(
 	git_repository *repo, const char *path, git_attr_file *ignores)
 {
 	int error = GIT_SUCCESS;
-	git_fbuffer fbuf = GIT_FBUFFER_INIT;
+	git_buf fbuf = GIT_BUF_INIT;
 	git_attr_fnmatch *match = NULL;
 	const char *scan = NULL;
 	char *context = NULL;
@@ -28,7 +28,7 @@ static int load_ignore_file(
 	if (error == GIT_SUCCESS)
 		error = git_futils_readbuffer(&fbuf, path);
 
-	scan = fbuf.data;
+	scan = fbuf.ptr;
 
 	while (error == GIT_SUCCESS && *scan) {
 		if (!match && !(match = git__calloc(1, sizeof(git_attr_fnmatch)))) {
@@ -53,7 +53,7 @@ static int load_ignore_file(
 		}
 	}
 
-	git_futils_freebuffer(&fbuf);
+	git_buf_free(&fbuf);
 	git__free(match);
 	git__free(context);
 
diff --git a/src/index.c b/src/index.c
index 4dccad527..5ac99de3e 100644
--- a/src/index.c
+++ b/src/index.c
@@ -216,7 +216,7 @@ void git_index_clear(git_index *index)
 int git_index_read(git_index *index)
 {
 	int error = GIT_SUCCESS, updated;
-	git_fbuffer buffer = GIT_FBUFFER_INIT;
+	git_buf buffer = GIT_BUF_INIT;
 	time_t mtime;
 
 	assert(index->index_file_path);
@@ -235,12 +235,12 @@ int git_index_read(git_index *index)
 
 	if (updated) {
 		git_index_clear(index);
-		error = parse_index(index, buffer.data, buffer.len);
+		error = parse_index(index, buffer.ptr, buffer.size);
 
 		if (error == GIT_SUCCESS)
 			index->last_modified = mtime;
 
-		git_futils_freebuffer(&buffer);
+		git_buf_free(&buffer);
 	}
 
 	if (error < GIT_SUCCESS)
diff --git a/src/odb.c b/src/odb.c
index 4eaf289e7..81fc82ba8 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -393,8 +393,8 @@ static int add_default_backends(git_odb *db, const char *objects_dir, int as_alt
 static int load_alternates(git_odb *odb, const char *objects_dir)
 {
 	git_buf alternates_path = GIT_BUF_INIT;
+	git_buf alternates_buf = GIT_BUF_INIT;
 	char *buffer;
-	git_fbuffer alternates_buf = GIT_FBUFFER_INIT;
 	const char *alternate;
 	int error;
 
@@ -412,7 +412,7 @@ static int load_alternates(git_odb *odb, const char *objects_dir)
 		return git__throw(GIT_EOSERR, "Failed to add backend. Can't read alternates");
 	}
 
-	buffer = (char *)alternates_buf.data;
+	buffer = (char *)alternates_buf.ptr;
 	error = GIT_SUCCESS;
 
 	/* add each alternate as a new backend; one alternate per line */
@@ -433,7 +433,8 @@ static int load_alternates(git_odb *odb, const char *objects_dir)
 	}
 
 	git_buf_free(&alternates_path);
-	git_futils_freebuffer(&alternates_buf);
+	git_buf_free(&alternates_buf);
+
 	if (error < GIT_SUCCESS)
 		return git__rethrow(error, "Failed to load alternates");
 	return error;
diff --git a/src/odb_loose.c b/src/odb_loose.c
index bb2b7b5f5..f5f6e35ac 100644
--- a/src/odb_loose.c
+++ b/src/odb_loose.c
@@ -75,13 +75,13 @@ static int object_file_name(git_buf *name, const char *dir, const git_oid *id)
 }
 
 
-static size_t get_binary_object_header(obj_hdr *hdr, git_fbuffer *obj)
+static size_t get_binary_object_header(obj_hdr *hdr, git_buf *obj)
 {
 	unsigned char c;
-	unsigned char *data = obj->data;
+	unsigned char *data = (unsigned char *)obj->ptr;
 	size_t shift, size, used = 0;
 
-	if (obj->len == 0)
+	if (obj->size == 0)
 		return 0;
 
 	c = data[used++];
@@ -90,7 +90,7 @@ static size_t get_binary_object_header(obj_hdr *hdr, git_fbuffer *obj)
 	size = c & 15;
 	shift = 4;
 	while (c & 0x80) {
-		if (obj->len <= used)
+		if (obj->size <= used)
 			return 0;
 		if (sizeof(size_t) * 8 <= shift)
 			return 0;
@@ -177,12 +177,12 @@ static void set_stream_output(z_stream *s, void *out, size_t len)
 }
 
 
-static int start_inflate(z_stream *s, git_fbuffer *obj, void *out, size_t len)
+static int start_inflate(z_stream *s, git_buf *obj, void *out, size_t len)
 {
 	int status;
 
 	init_stream(s, out, len);
-	set_stream_input(s, obj->data, obj->len);
+	set_stream_input(s, obj->ptr, obj->size);
 
 	if ((status = inflateInit(s)) < Z_OK)
 		return status;
@@ -287,7 +287,7 @@ static void *inflate_tail(z_stream *s, void *hb, size_t used, obj_hdr *hdr)
  * of loose object data into packs. This format is no longer used, but
  * we must still read it.
  */
-static int inflate_packlike_loose_disk_obj(git_rawobj *out, git_fbuffer *obj)
+static int inflate_packlike_loose_disk_obj(git_rawobj *out, git_buf *obj)
 {
 	unsigned char *in, *buf;
 	obj_hdr hdr;
@@ -310,8 +310,8 @@ static int inflate_packlike_loose_disk_obj(git_rawobj *out, git_fbuffer *obj)
 	if (!buf)
 		return GIT_ENOMEM;
 
-	in = ((unsigned char *)obj->data) + used;
-	len = obj->len - used;
+	in = ((unsigned char *)obj->ptr) + used;
+	len = obj->size - used;
 	if (inflate_buffer(in, len, buf, hdr.size)) {
 		git__free(buf);
 		return git__throw(GIT_ERROR, "Failed to inflate loose object. Could not inflate buffer");
@@ -325,7 +325,7 @@ static int inflate_packlike_loose_disk_obj(git_rawobj *out, git_fbuffer *obj)
 	return GIT_SUCCESS;
 }
 
-static int inflate_disk_obj(git_rawobj *out, git_fbuffer *obj)
+static int inflate_disk_obj(git_rawobj *out, git_buf *obj)
 {
 	unsigned char head[64], *buf;
 	z_stream zs;
@@ -335,7 +335,7 @@ static int inflate_disk_obj(git_rawobj *out, git_fbuffer *obj)
 	/*
 	 * check for a pack-like loose object
 	 */
-	if (!is_zlib_compressed_data(obj->data))
+	if (!is_zlib_compressed_data((unsigned char *)obj->ptr))
 		return inflate_packlike_loose_disk_obj(out, obj);
 
 	/*
@@ -383,7 +383,7 @@ static int inflate_disk_obj(git_rawobj *out, git_fbuffer *obj)
 static int read_loose(git_rawobj *out, git_buf *loc)
 {
 	int error;
-	git_fbuffer obj = GIT_FBUFFER_INIT;
+	git_buf obj = GIT_BUF_INIT;
 
 	assert(out && loc);
 
@@ -398,7 +398,7 @@ static int read_loose(git_rawobj *out, git_buf *loc)
 		return git__throw(GIT_ENOTFOUND, "Failed to read loose object. File not found");
 
 	error = inflate_disk_obj(out, &obj);
-	git_futils_freebuffer(&obj);
+	git_buf_free(&obj);
 
 	return error == GIT_SUCCESS ? GIT_SUCCESS : git__rethrow(error, "Failed to read loose object");
 }
diff --git a/src/reflog.c b/src/reflog.c
index 9f5ccd322..6ca9418cf 100644
--- a/src/reflog.c
+++ b/src/reflog.c
@@ -183,7 +183,7 @@ int git_reflog_read(git_reflog **reflog, git_reference *ref)
 {
 	int error;
 	git_buf log_path = GIT_BUF_INIT;
-	git_fbuffer log_file = GIT_FBUFFER_INIT;
+	git_buf log_file = GIT_BUF_INIT;
 	git_reflog *log = NULL;
 
 	*reflog = NULL;
@@ -201,7 +201,7 @@ int git_reflog_read(git_reflog **reflog, git_reference *ref)
 		goto cleanup;
 	}
 
-	if ((error = reflog_parse(log, log_file.data, log_file.len)) < GIT_SUCCESS)
+	if ((error = reflog_parse(log, log_file.ptr, log_file.size)) < GIT_SUCCESS)
 		git__rethrow(error, "Failed to read reflog");
 	else
 		*reflog = log;
@@ -209,7 +209,7 @@ int git_reflog_read(git_reflog **reflog, git_reference *ref)
 cleanup:
 	if (error != GIT_SUCCESS && log != NULL)
 		git_reflog_free(log);
-	git_futils_freebuffer(&log_file);
+	git_buf_free(&log_file);
 	git_buf_free(&log_path);
 
 	return error;
diff --git a/src/refs.c b/src/refs.c
index 8e911c1ae..2e1d92da2 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -32,15 +32,15 @@ struct packref {
 static const int default_table_size = 32;
 
 static int reference_read(
-	git_fbuffer *file_content,
+	git_buf *file_content,
 	time_t *mtime,
 	const char *repo_path,
 	const char *ref_name,
 	int *updated);
 
 /* loose refs */
-static int loose_parse_symbolic(git_reference *ref, git_fbuffer *file_content);
-static int loose_parse_oid(git_oid *ref, git_fbuffer *file_content);
+static int loose_parse_symbolic(git_reference *ref, git_buf *file_content);
+static int loose_parse_oid(git_oid *ref, git_buf *file_content);
 static int loose_lookup(git_reference *ref);
 static int loose_lookup_to_packfile(struct packref **ref_out,
 	git_repository *repo, const char *name);
@@ -113,7 +113,7 @@ static int reference_alloc(
 	return GIT_SUCCESS;
 }
 
-static int reference_read(git_fbuffer *file_content, time_t *mtime, const char *repo_path, const char *ref_name, int *updated)
+static int reference_read(git_buf *file_content, time_t *mtime, const char *repo_path, const char *ref_name, int *updated)
 {
 	git_buf path = GIT_BUF_INIT;
 	int     error = GIT_SUCCESS;
@@ -129,15 +129,15 @@ static int reference_read(git_fbuffer *file_content, time_t *mtime, const char *
 	return error;
 }
 
-static int loose_parse_symbolic(git_reference *ref, git_fbuffer *file_content)
+static int loose_parse_symbolic(git_reference *ref, git_buf *file_content)
 {
 	const unsigned int header_len = strlen(GIT_SYMREF);
 	const char *refname_start;
 	char *eol;
 
-	refname_start = (const char *)file_content->data;
+	refname_start = (const char *)file_content->ptr;
 
-	if (file_content->len < (header_len + 1))
+	if (file_content->size < (header_len + 1))
 		return git__throw(GIT_EOBJCORRUPTED,
 			"Failed to parse loose reference. Object too short");
 
@@ -165,15 +165,15 @@ static int loose_parse_symbolic(git_reference *ref, git_fbuffer *file_content)
 	return GIT_SUCCESS;
 }
 
-static int loose_parse_oid(git_oid *oid, git_fbuffer *file_content)
+static int loose_parse_oid(git_oid *oid, git_buf *file_content)
 {
 	int error;
 	char *buffer;
 
-	buffer = (char *)file_content->data;
+	buffer = (char *)file_content->ptr;
 
 	/* File format: 40 chars (OID) + newline */
-	if (file_content->len < GIT_OID_HEXSZ + 1)
+	if (file_content->size < GIT_OID_HEXSZ + 1)
 		return git__throw(GIT_EOBJCORRUPTED,
 			"Failed to parse loose reference. Reference too short");
 
@@ -193,26 +193,26 @@ static int loose_parse_oid(git_oid *oid, git_fbuffer *file_content)
 
 static git_rtype loose_guess_rtype(const git_buf *full_path)
 {
-	git_fbuffer ref_file = GIT_FBUFFER_INIT;
+	git_buf ref_file = GIT_BUF_INIT;
 	git_rtype type;
 
 	type = GIT_REF_INVALID;
 
 	if (git_futils_readbuffer(&ref_file, full_path->ptr) == GIT_SUCCESS) {
-		if (git__prefixcmp((const char *)(ref_file.data), GIT_SYMREF) == 0)
+		if (git__prefixcmp((const char *)(ref_file.ptr), GIT_SYMREF) == 0)
 			type = GIT_REF_SYMBOLIC;
 		else
 			type = GIT_REF_OID;
 	}
 
-	git_futils_freebuffer(&ref_file);
+	git_buf_free(&ref_file);
 	return type;
 }
 
 static int loose_lookup(git_reference *ref)
 {
 	int error = GIT_SUCCESS, updated;
-	git_fbuffer ref_file = GIT_FBUFFER_INIT;
+	git_buf ref_file = GIT_BUF_INIT;
 
 	if (reference_read(&ref_file, &ref->mtime,
 			ref->owner->path_repository, ref->name, &updated) < GIT_SUCCESS)
@@ -228,7 +228,7 @@ static int loose_lookup(git_reference *ref)
 
 	ref->flags = 0;
 
-	if (git__prefixcmp((const char *)(ref_file.data), GIT_SYMREF) == 0) {
+	if (git__prefixcmp((const char *)(ref_file.ptr), GIT_SYMREF) == 0) {
 		ref->flags |= GIT_REF_SYMBOLIC;
 		error = loose_parse_symbolic(ref, &ref_file);
 	} else {
@@ -236,7 +236,7 @@ static int loose_lookup(git_reference *ref)
 		error = loose_parse_oid(&ref->target.oid, &ref_file);
 	}
 
-	git_futils_freebuffer(&ref_file);
+	git_buf_free(&ref_file);
 
 	if (error < GIT_SUCCESS)
 		return git__rethrow(error, "Failed to lookup loose reference");
@@ -250,7 +250,7 @@ static int loose_lookup_to_packfile(
 		const char *name)
 {
 	int error = GIT_SUCCESS;
-	git_fbuffer ref_file = GIT_FBUFFER_INIT;
+	git_buf ref_file = GIT_BUF_INIT;
 	struct packref *ref = NULL;
 	size_t name_len;
 
@@ -273,11 +273,11 @@ static int loose_lookup_to_packfile(
 	ref->flags = GIT_PACKREF_WAS_LOOSE;
 
 	*ref_out = ref;
-	git_futils_freebuffer(&ref_file);
+	git_buf_free(&ref_file);
 	return GIT_SUCCESS;
 
 cleanup:
-	git_futils_freebuffer(&ref_file);
+	git_buf_free(&ref_file);
 	free(ref);
 	return git__rethrow(error, "Failed to lookup loose reference");
 }
@@ -427,7 +427,7 @@ cleanup:
 static int packed_load(git_repository *repo)
 {
 	int error = GIT_SUCCESS, updated;
-	git_fbuffer packfile = GIT_FBUFFER_INIT;
+	git_buf packfile = GIT_BUF_INIT;
 	const char *buffer_start, *buffer_end;
 	git_refcache *ref_cache = &repo->references;
 
@@ -468,8 +468,8 @@ static int packed_load(git_repository *repo)
 
 	git_hashtable_clear(ref_cache->packfile);
 
-	buffer_start = (const char *)packfile.data;
-	buffer_end = (const char *)(buffer_start) + packfile.len;
+	buffer_start = (const char *)packfile.ptr;
+	buffer_end = (const char *)(buffer_start) + packfile.size;
 
 	while (buffer_start < buffer_end && buffer_start[0] == '#') {
 		buffer_start = strchr(buffer_start, '\n');
@@ -500,13 +500,13 @@ static int packed_load(git_repository *repo)
 		}
 	}
 
-	git_futils_freebuffer(&packfile);
+	git_buf_free(&packfile);
 	return GIT_SUCCESS;
 
 cleanup:
 	git_hashtable_free(ref_cache->packfile);
 	ref_cache->packfile = NULL;
-	git_futils_freebuffer(&packfile);
+	git_buf_free(&packfile);
 	return git__rethrow(error, "Failed to load packed references");
 }
 
diff --git a/src/repository.c b/src/repository.c
index f394d06fe..c46dd9df9 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -467,7 +467,7 @@ static int retrieve_ceiling_directories_offset(
  */
 static int read_gitfile(git_buf *path_out, const char *file_path, const char *base_path)
 {
-	git_fbuffer file;
+	git_buf file = GIT_BUF_INIT;
 	int error;
 
 	assert(path_out && file_path);
@@ -476,22 +476,22 @@ static int read_gitfile(git_buf *path_out, const char *file_path, const char *ba
 	if (error < GIT_SUCCESS)
 		return error;
 
-	if (git__prefixcmp((char *)file.data, GIT_FILE_CONTENT_PREFIX)) {
-		git_futils_freebuffer(&file);
+	if (git__prefixcmp((char *)file.ptr, GIT_FILE_CONTENT_PREFIX)) {
+		git_buf_free(&file);
 		return git__throw(GIT_ENOTFOUND, "Invalid gitfile format `%s`", file_path);
 	}
 
-	git_futils_fbuffer_rtrim(&file);
+	git_buf_rtrim(&file);
 
-	if (strlen(GIT_FILE_CONTENT_PREFIX) == file.len) {
-		git_futils_freebuffer(&file);
+	if (strlen(GIT_FILE_CONTENT_PREFIX) == file.size) {
+		git_buf_free(&file);
 		return git__throw(GIT_ENOTFOUND, "No path in git file `%s`", file_path);
 	}
 
 	error = git_path_prettify_dir(path_out,
-		((char *)file.data) + strlen(GIT_FILE_CONTENT_PREFIX), base_path);
+		((char *)file.ptr) + strlen(GIT_FILE_CONTENT_PREFIX), base_path);
 
-	git_futils_freebuffer(&file);
+	git_buf_free(&file);
 
 	if (error == GIT_SUCCESS && git_path_exists(path_out->ptr) == 0)
 		return GIT_SUCCESS;
diff --git a/tests-clar/core/buffer.c b/tests-clar/core/buffer.c
index 740cd8578..870525b36 100644
--- a/tests-clar/core/buffer.c
+++ b/tests-clar/core/buffer.c
@@ -218,8 +218,8 @@ check_buf_append(
 	const char* data_a,
 	const char* data_b,
 	const char* expected_data,
-	ssize_t expected_size,
-	ssize_t expected_asize)
+	size_t expected_size,
+	size_t expected_asize)
 {
 	git_buf tgt = GIT_BUF_INIT;
 
@@ -371,8 +371,8 @@ void test_core_buffer__7(void)
 	git_buf_attach(&a, b, 0);
 
 	cl_assert_strequal(fun, a.ptr);
-	cl_assert(a.size == (ssize_t)strlen(fun));
-	cl_assert(a.asize == (ssize_t)strlen(fun) + 1);
+	cl_assert(a.size == strlen(fun));
+	cl_assert(a.asize == strlen(fun) + 1);
 
 	git_buf_free(&a);
 
@@ -380,8 +380,8 @@ void test_core_buffer__7(void)
 	git_buf_attach(&a, b, strlen(fun) + 1);
 
 	cl_assert_strequal(fun, a.ptr);
-	cl_assert(a.size == (ssize_t)strlen(fun));
-	cl_assert(a.asize == (ssize_t)strlen(fun) + 1);
+	cl_assert(a.size == strlen(fun));
+	cl_assert(a.asize == strlen(fun) + 1);
 
 	git_buf_free(&a);
 }
diff --git a/tests-clar/core/path.c b/tests-clar/core/path.c
index 3ff5d7daf..c07362f1d 100644
--- a/tests-clar/core/path.c
+++ b/tests-clar/core/path.c
@@ -243,7 +243,7 @@ void test_core_path__07_path_to_dir(void)
 void test_core_path__08_self_join(void)
 {
 	git_buf path = GIT_BUF_INIT;
-	ssize_t asize = 0;
+	size_t asize = 0;
 
 	asize = path.asize;
 	cl_git_pass(git_buf_sets(&path, "/foo"));
diff --git a/tests/test_helpers.c b/tests/test_helpers.c
index 42c8031cd..837358453 100644
--- a/tests/test_helpers.c
+++ b/tests/test_helpers.c
@@ -182,7 +182,7 @@ int cmp_objects(git_rawobj *o, object_data *d)
 
 int copy_file(const char *src, const char *dst)
 {
-	git_fbuffer source_buf;
+	git_buf source_buf = GIT_BUF_INIT;
 	git_file dst_fd;
 	int error = GIT_ERROR;
 
@@ -193,10 +193,10 @@ int copy_file(const char *src, const char *dst)
 	if (dst_fd < 0)
 		goto cleanup;
 
-	error = p_write(dst_fd, source_buf.data, source_buf.len);
+	error = p_write(dst_fd, source_buf.ptr, source_buf.size);
 
 cleanup:
-	git_futils_freebuffer(&source_buf);
+	git_buf_free(&source_buf);
 	p_close(dst_fd);
 
 	return error;
@@ -204,22 +204,23 @@ cleanup:
 
 int cmp_files(const char *a, const char *b)
 {
-	git_fbuffer buf_a, buf_b;
+	git_buf buf_a = GIT_BUF_INIT;
+	git_buf buf_b = GIT_BUF_INIT;
 	int error = GIT_ERROR;
 
 	if (git_futils_readbuffer(&buf_a, a) < GIT_SUCCESS)
 		return GIT_ERROR;
 
 	if (git_futils_readbuffer(&buf_b, b) < GIT_SUCCESS) {
-		git_futils_freebuffer(&buf_a);
+		git_buf_free(&buf_a);
 		return GIT_ERROR;
 	}
 
-	if (buf_a.len == buf_b.len && !memcmp(buf_a.data, buf_b.data, buf_a.len))
+	if (buf_a.size == buf_b.size && !memcmp(buf_a.ptr, buf_b.ptr, buf_a.size))
 		error = GIT_SUCCESS;
 
-	git_futils_freebuffer(&buf_a);
-	git_futils_freebuffer(&buf_b);
+	git_buf_free(&buf_a);
+	git_buf_free(&buf_b);
 
 	return error;
 }